The invention relates to a subassembly for the front and rear region of a motor vehicle, which comprises two longitudinal members to which a subframe designed as assembly carrier is attached by one end region of two elongate carrier parts, which members are together used for energy absorption in the case of a vehicle impact and which are fixed by their ends, which project as far as a passenger compartment, with lateral longitudinal members reinforcing the latter at the vehicle floor.
A subassembly of this kind, which is deformable in the case of a vehicle impact and thereby reduces the deforming action of an impact energy on the passenger compartment, has been disclosed for a front region of a vehicle in German Patent Document DE-OS 3,146,554. In this arrangement, a subframe is attached at the front and additionally in the vicinity of the passenger compartment, to longitudinal members, and by the latter to a vehicle floor having lateral door sills. It is thereby intended to ensure that the subframe is used to absorb force in the case of a frontal impact in that stop surfaces on the subframe can be brought up against a passenger-compartment front wall connected to the longitudinal members.
In German Patent Document DE-OS 3, 522, 447, a vehicle is equipped with a subframe which has two longitudinal members and one cross member and, together with a laterally spaced one of the longitudinal members of the body situated on both sides forms a rigid unit which is intended to transmit the impact forces on the subframe into the laterally spaced longitudinal members of the vehicle superstructure proper.
The particular disadvantage of the embodiments of both printed publications is that the forward structure of the vehicle is intrinsically of very stable design, with the result that, in the case of an accident, the impact energy is reduced only slightly by deformation of the carrier parts of the forward structure, or the energy remaining after their deformation is transmitted directly into the passenger-compartment front wall, with the result that it is possible to protect the passenger compartment from deformations only inadequately. An already know deformation of the longitudinal members, possible over a long distance, is prevented by the subframe.
An object on which the invention is based is to design a subassembly of the above noted type in such a way that the subframe permits the deformation of a longitudinal member and reduces the transmission of the impact energy into a passenger compartment.
This object is achieved by providing arrangements wherein the carrier parts extend freely after they have been fixed on the longitudinal members respectively with a portion oriented approximately in the longitudinal direction of the vehicle towards the passenger compartment and are guided with an obtuse-angled bend about a vertical axis towards the respectively proximate lateral spaced longitudinal members of the vehicle super structure proper and are attached to the latter.
By connecting a subframe to the two longitudinal members of the body in such a way and, by the other ends, to laterally spaced longitudinal members at the vehicle floor and by the special shape of the subframe carrier parts, the deformation of the longitudinal members of the body can take place over a long distance in the case of an accident without hindrance by the subframe. Due to its controlled deformation in the region of the bend, the subframe likewise reduces impact energy. During this process, it remains fixed to the body at its points of attachment and thus does not have to unlatch in an accident to enable a deformation in the region of the longitudinal members to take place.
The subframe cross member, which does not hinder the further bending of the subframe carrier parts oriented approximately in the longitudinal direction of the vehicle, has a stabilizing effect for the guidance of the subframe towards the passenger compartment and prevents the subframe carrier parts from bending out.
It is, furthermore, advantageous to deflect the subframe downwards along a slope during its displacement, i.e. to deflect it under the passenger compartment, so that a passenger-compartment front wall is not damaged or deformed by the displaced subframe.
Furthermore, the bent portion of the subframe carrier parts comes to lie in front of the vehicle wheels, which may likewise be moved towards the passenger compartment, and thereby prevents them from penetrating.
In order to avoid transmission of the assembly vibrations to the vehicle body via the subframe to the greatest possible extent, the carrier parts of the subframe are mounted resiliently on the vehicle floor via rubber elements.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.